News TSMC Records First Coronavirus Case in Taiwan Facility

If that employee did not get tested until symptoms became apparent, then everyone who has been in contact with him within the past 10-15 days may also be contaminated. I'd be surprised if that was only 30 employees and any of those employees who are also infected may have been spreading it around for some number of days too.

With the long incubation period, you won't know for certain how effective containment efforts have been until 15-20 days later.